To open a floating window on an Android device, you can typically follow these steps:

1. Swipe down from the top of the screen to access the notification panel.
2. Look for an icon or option that represents the floating window feature (it y vary depending on the device and software version).
3. Tap on the icon or option to activate the floating window.
4. You can then drag and resize the floating window on your screen as needed.

If you are looking for code to create a floating window in an Android app, here is a basic example using Kotlin:

```kotlin
// Create a new floating window
val params = WindowManager.LayoutParams(
WindowManager.LayoutParams.WRAP_CONTENT,
WindowManager.LayoutParams.WRAP_CONTENT,
WindowManager.LayoutParams.TYPE_APPLICATION_OVERLAY,
WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE,
PixelFor t.TRANSLUCENT
)

val windowManager = getSystemService(Context.WINDOW_SERVICE) as WindowManager
val view = LayoutInflater.from(this).inflate(R.layout.floating_window_layout, null)

windowManager.addView(view, params)
```

Please note that the above code snippet is just a basic example and y need to be adjusted based on your specific requirements and the structure of your app.